基于MATLAB的车道线检测

一、核心算法流程

graph TD A[图像输入] --> B{预处理} B --> C[灰度转换] B --> D[ROI区域限制] C --> E[边缘检测] D --> E E --> F[颜色空间增强] F --> G[霍夫变换检测] G --> H[直线聚类] H --> I[曲线拟合] I --> J[结果可视化]

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二、分步实现代码

1. 图像预处理

% 读取图像
img = imread('road_scene.jpg');
figure; imshow(img); title('原始图像');

% 转换为LAB色彩空间增强对比度
labImg = rgb2lab(img);
L = labImg(:,:,1)/100;
L = adapthisteq(L); % 自适应直方图均衡化
labImg(:,:,1) = L*100;
enhancedImg = lab2rgb(labImg);

% ROI区域设置（梯形区域）
mask = poly2mask([1, size(img,2), size(img,2)/2], ...
                 [1, 1, size(img,1)], size(img,1), size(img,2));
maskedImg = bsxfun(@times, double(enhancedImg), cast(mask, 'like', enhancedImg));

2. 边缘检测与颜色阈值

% Canny边缘检测
edges = edge(maskedImg(:,:,1), 'Canny', [0.1, 0.3]);

% 颜色阈值提取车道线（白色+黄色）
whiteMask = (maskedImg(:,:,1) > 240) & (maskedImg(:,:,2) < 30) & (maskedImg(:,:,3) < 30);
yellowMask = (maskedImg(:,:,1) > 180) & (maskedImg(:,:,2) > 150) & (maskedImg(:,:,3) < 80);
combinedMask = imbinarize(edges) | whiteMask | yellowMask;

3. 霍夫变换检测

% 霍夫变换参数设置
[H, theta, rho] = hough(combinedMask, 0.1 * 2*pi, 1, 200);
peaks = houghpeaks(H, 50, 'threshold', 0.3*max(H(:)));
lines = houghlines(combinedMask, theta, rho, peaks, 'FillGap', 30, 'MinLength', 50);

% 绘制检测结果
figure; imshow(img); hold on;
for k = 1:length(lines)
    xy = [lines(k).point1; lines(k).point2];
    plot(xy(:,1), xy(:,2), 'LineWidth', 2, 'Color', 'green');
end

4. 车道线聚类与拟合

% 线段聚类（基于斜率分组）
leftLines = [];
rightLines = [];
for i = 1:length(lines)
    slope = (lines(i).point2(2) - lines(i).point1(2)) / ...
            (lines(i).point2(1) - lines(i).point1(1));
    if slope < -0.5
        leftLines = [leftLines; lines(i)];
    elseif slope > 0.5
        rightLines = [rightLines; lines(i)];
    end
end

% 二次曲线拟合
leftFit = polyfit(mean([leftLines.point1; leftLines.point2], 1), 2);
rightFit = polyfit(mean([rightLines.point1; rightLines.point2], 1), 2);

% 生成拟合曲线
plotLane(leftFit, 'r', 3);
plotLane(rightFit, 'b', 3);

function plotLane(coeffs, color, width)
    xRange = 1:size(img,2);
    yRange = polyval(coeffs, xRange);
    plot(xRange, yRange, color, 'LineWidth', width);
end

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三、关键优化策略

1. 动态ROI调整（自适应车道区域）

% 基于消失点检测的ROI动态调整
[vp, ~] = detectVanishingPoint(combinedMask);
if ~isempty(vp)
    [x1,y1] = convertPointsToHomogeneous(vp);
    roiPoints = [1, size(img,2); 1, 1; x1, y1];
    mask = poly2mask(roiPoints(:,1), roiPoints(:,2), size(img,1));
end

2. 多尺度检测（适应不同分辨率）

% 图像金字塔处理
pyramid = imagePyramid(img, 'ScaleFactor', 0.5, 'NumLevels', 3);
for i = 1:numel(pyramid)
    processLevel(pyramid{i});
end

function processLevel(img)
    % 各尺度独立处理
end

3. 深度学习辅助（预训练模型）

% 使用预训练CNN提取特征
net = alexnet;
featureLayer = 'fc7';
featureMap = activations(net, img, featureLayer);

% 结合传统方法进行车道线检测

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四、完整处理流程示例

% 1. 加载测试图像
img = imread('highway.jpg');

% 2. 预处理
preprocessed = preprocessImage(img);

% 3. 边缘检测与颜色阈值
edges = detectEdges(preprocessed);

% 4. 霍夫变换检测
lines = detectHoughLines(edges);

% 5. 车道线聚类与拟合
leftFit = fitLeftLane(lines);
rightFit = fitRightLane(lines);

% 6. 结果可视化
visualizeLane(img, leftFit, rightFit);

参考代码 基于matlab 实现对图片的车道线检测 www.youwenfan.com/contentcnj/63292.html

五、性能评估指标

% 计算检测准确率
groundTruth = load('ground_truth.mat'); % 包含真实车道线坐标
TP = calculateTruePositives(detectedLines, groundTruth);
precision = TP / numel(detectedLines);
recall = TP / numel(groundTruth);

% 可视化评估结果
plotConfusionMatrix(groundTruth, detectedLines);

六、典型应用场景优化

1. 夜间场景处理

% 增强低光照区域
img = enhanceLowLight(img);
% 使用形态学操作连接断裂边缘
se = strel('disk',3);
morphImg = imclose(edges, se);

2. 弯道场景处理

% 三次样条曲线拟合
t = linspace(0,1,numel(detectedPoints));
x = polyval(coeffs(:,1), t);
y = polyval(coeffs(:,2), t);
splineFit = spline(t, [x; y]);

3. 实时视频处理

videoReader = VideoReader('road_video.mp4');
while hasFrame(videoReader)
    frame = readFrame(videoReader);
    processedFrame = processFrame(frame);
    imshow(processedFrame);
    drawnow;
end